@Terri292,
As @Colleen253 points out, you need to know what are the short-term rental and tenant's right regulations where your listing is located. In Georgia, a short-term rental is less than 90 days. I accept long-term stays, but insist that my guests make multiple 30 day bookings for not longer than three consecutive months instead of one long multi-month reservation to insure that I receive payment each month, because Airbnb only guarantees the first month's payment (search this board about non-payment for long-term stays), and to cover the cleaning fee. Also, the 30 day stays gives us both an easy out if either of us determine that the arrangement is no longer a good fit. My rental is connected to my home, and I think that had helped keep people in line as far as not creating damages. Next month, we will have a returning guest that will stay for three months. Since we will not be onsite for the full duration of his stay, similar to @Ann72, we will require regular cleanings, but it will occur every two weeks.
I think you have a very nice space, and it's a very good price for two people, but you are downright giving it away for eight people. The monthly rate for eight people breaks down to $11.38 per person/per night, excluding taxes and fees. Is it only a couple that wants to stay in the place? If so, I would question why they need three bedrooms. Update you house rules, and be emphatic that only registered guests may stay overnight in the space. Unless you're going to have regular cleanings done, the $100 cleaning fee for most short-term rentals, will likely not be enough, and the place will need an extra-deep cleaning after a three month stay.